Turning on the clock

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Science  25 Jan 2019:
Vol. 363, Issue 6425, pp. 361-362
DOI: 10.1126/science.363.6425.361-f

Every day we wake and sleep under the control of the brain's master clock or suprachiasmatic nucleus (SCN). If the SCN's key cryptochrome (Cry) protein components are globally deleted, the clock is disabled. Maywood et al. have developed molecular tools to study the clock's complex transcriptional and translational feedback loops. A translational switch was designed, by expanding the genetic code, to reversibly control translation of Cry1 in the SCN. This allows an orthogonal aminoacyl–transfer RNA (tRNA) synthetase–tRNA pair to be targeted to the SCN by adeno-associated virus vectors. Cry1 is then only expressed in the SCN when a noncanonical amino acid is supplied. By using this tool, Cry1 expression can be induced in Cry-null mice to initiate circadian behavior in the otherwise arrhythmic mice.

Proc. Natl. Acad. Sci. U.S.A. 115, E12388 (2018).

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